Metazoan parasites on the gills of the skipjack tuna Katsuwonus pelamis (Osteichthyes: Scombridae) from the Alboran Sea (western Mediterranean Sea)

Abstract

The gills of 31 skipjack tuna Katsuwonus pelamis (L.) caught in the Alboran Sea (western Mediterranean Sea) were examined for metazoan parasites, and the gills of 4 specimens from the Balearic Sea (also western Mediterranean Sea) were analysed for comparative purposes. Nine species of parasites were found, including 8 didymozoid trematodes (Atalostrophion cf. biovarium, Didymocylindrus filiformis, Didymocylindrus simplex, Didymocystis reniformis, Didymoproblema fusiforme, Didymozoon longicolle, Koellikeria sp. and Lobatozoum multisacculatum) and 1 caligid copepod (Caligus bonito). Koellikeria sp. and L. multisacculatum were not recorded in the Balearic Sea. Most of the parasites (79.2% of all specimens) were didymozoids. Didymozoon longicolle was the dominant species; A. cf. biovarium, D. simplex, D. fusiforme and L. multisacculatum are reported from the Mediterranean Sea for the first time. No correlation was found between the intensity of infection of any parasite species and host size or sex. Most of the parasites, particularly didymozoids, showed a high site-specificity. Significant differences were found between the parasite assemblages of K. pelamis from the Alboran Sea and from the Atlantic Ocean. D. fusiforme, D. longicolle and L. multisacculatum are suggested as potential tags to follow skipjack tuna migrations between the Atlantic Ocean and Mediterranean Sea.

Factors linked to interannual variation in the metazoan parasite communities of black skipjack, Euthynnus lineatus (Pisces: Scombridae)

“…Crustaceans were the second‐most diverse parasite group (three copepods and three isopods) and represented 18.2% of total species; however, this group's numerical dominance was quite low (0.28% of total individual parasites). Apparently the crustaceans are not abundant and frequent in scombrid fish; only one to four species (including C. bonito , reported here) have been recorded in the parasite communities of these marine fish (Alves & Luque, ; Chero et al, ; Hermida, Cavaleiro, Gouveia, & Saraiva, ; Mele et al, ).…”

“…Didymozoid digeneans (nine identified species and one larva) numerically dominated the parasite communities, representing 77% of total recovered individual parasites. Digeneans of the family Didymozoidae are parasites of marine fish with high host specificity: they mainly parasitize tropical and subtropical scombrids and are rarely found in freshwater fish species (Madhavi & Ram, ; Mele et al, ; Nascimento‐Justo & Kohn, ; Nikolaeva, ). Parasites from this group were found encapsulated in pairs (e.g., Koellikeria sp.…”

Metazoan parasites in the head region of the bullet tuna Auxisrochei (Osteichthyes: Scombridae) from the western Mediterranean Sea

“…; Cressey & Cressey, 1980;Ö ktener & Trilles, 2009). In the Mediterranean Sea A. macrova seems to be restricted to A. rochei, since this monogenean was not found in 156 Euthynnus alletteratus and 35 K. pelamis caught within the same sampling programme (Mele, 2013). The cross-infection of A. macrova among the Mediterranean tuna could be limited by the different life history and habitat of hosts (Reglero et al, 2012;Rodríguez et al, 2013).…”

Parasites of the head of Scomber colias (Osteichthyes: Scombridae) from the western Mediterranean Sea

“…For example, Halvorsenius exilis has been reported from Madeira (Oliva et al 2008) Ocean. In fact, several didymozoids have been recorded outside their endemic areas (Lester et al 1985;Mele et al 2012), because they cannot leave their hosts, being encysted in the host tissues (Pascual et al 2006). The distance could be a barrier to the spread of these didymozoids between the opposite coasts of the Atlantic Ocean, as also showed for several mazocraeids (K. sprostonae, P. minor); whereas the different oceanographic conditions between the eastern and western Mediterranean Seas (Robison et al 2001;Manca et al 2004), which can support a different macro fauna (Garibaldi 1998), can be an important factor that could explain the different trematode faunas of these basins (Gargouri Ben Abdalah et al 2010;Culurgioni et al 2014).…”